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Book Review

Hothouse Earth: An Inhabitant’s Guide
by Bill McGuire
Reviewed by John Horseley

Bill McGuire is an emeritus professor of geophysical and climate hazards at University College London. In “Hothouse Earth” he presents an alarming picture of the sort of world we can expect to inhabit as the climate crisis unfolds.

The average temperature of the Earth has increased by about 1.2° C since pre-industrial times and this is already having an enormous impact worldwide, most obviously in the increase in the intensity and frequency of extreme weather events such as record-breaking heat waves, floods and droughts. (In a recent interview Bill McGuire has stated  that no one, including climate scientists, expected such a small rise in average global temperature to bring about such extreme weather conditions so rapidly).

However, present conditions are relatively mild compared to what is in store when the average temperature rises further (Bill McGuire considers that an increase of 1.5° C in the next few years is inevitable and we are probably headed towards an increase of at least 2.3° C). Some of the heat waves will become especially deadly due to a combination of heat and humidity that the human body is not able to handle, leading to mass fatalities (a fictional heat wave of this type is described in Kim Stanley Robinson’s novel “The Ministry for the Future”). These heat waves will make large parts of the planet uninhabitable.

Droughts will also seriously impact food supply in many areas leading to civil disorder and many millions of climate refugees.  Rising sea levels (at least 3 feet by the end of the century) will flood land that is home to 400 million people. The the melting of the Greenland and Antarctic ice sheets could make this forecast too optimistic. Rising temperatures will greatly increase the numbers of disease-bearing insects, especially mosquitoes, which will spread diseases such as malaria into regions where these diseases were thought to have disappeared.

Among the great unknowns of climate change are the tipping points at which catastrophic change becomes irreversible. Will the influx of cold water from the melting of the Greenland ice cap cause the collapse of the Gulf Stream, which keeps the climate of Europe temperate?  Will the melting permafrost in the Arctic cause a massive increase in methane emissions, leading to rapid uncontrollable global heating? (A recent study published in the journal Science has identified multiple dangerous climate tipping points that could be triggered by a rise in temperature of 1.5° C and it is even possible that it is already too late to avoid some of them).

Bill McGuire does not believe that any of the proposed technical fixes for climate change can come to our rescue. As a volcanologist he is especially critical of the most popular proposal for geoengineering – to simulate the cooling effect of a volcanic eruption by seeding the atmosphere with sulfur aerosols.  He also dismisses a developing technology that collects carbon emissions at their source and stores them underground (carbon capture and storage). There are indeed enormous challenges with implementing  this technology at large scale, but it is considered to be essential if the 2050 net zero carbon emissions goal is to be met.

Bill McGuire puts the blame for our present predicament squarely on free market capitalism, which is not sustainable on a planet with limited resources. Some measure of a successful economy other than GDP growth is needed.  The transition to a more sustainable economy will not be easy but he believes it can be accomplished with enough political will.  Dangerous climate breakdown is now inevitable but we have the means to avoid worst case scenarios if we can make this transition.

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